I recently read your article describing the study on the efficacy of fertilizer bans. As a landscape contractor, horticulturalist, and ornamental pest control operator, I really try to do what is best for our community and our bay. As you well know, the research and agreement amongst the “experts” is contentious to say the least. To have a study that answers all of the local competing science will no doubt be grand!
I have a few questions about your study and the bay on the whole. Ultimately your study results will be of assistance, but for now, any insight would be appreciated.
1. Every entity concerned about water quality in the bay (TBEP, DEP, Sierra Club, Pinellas County, City of Tampa, SWFWMD, Extension, and many more) all advise that if one utilizes “reclaimed water,” then curtail fertilizer usage. Yet, seemingly no one is addressing the fact that the City of Tampa is loading 55 MILLION gallons of (nitrogen-containing) treated wastewater — potential reclaimed water into the bay daily. Are the nitrogen amounts in reclaimed water high enough for landscape usage and augmentation, but not high enough to harm the bay? Please help me understand the numbers.
2. How much loading does residential fertilizer use account for relative to other nitrogen inputs, such as the City of Tampa reclaimed treated wastewater (if indeed this is a problem), farm operations in east Hillsborough county (if indeed their practices make their way to the bay), septic tanks, industrial usage, etc. into the bay? And, are your current “residential” usage amounts strictly residential usage rates (ie: homeowners), or does it include municipal usage (parks, recreation fields, etc.), certified pest control operators, theme park usage, golf courses, etc.? Can you separate input sources?
I ask because a recent study I read by IFAS reported that municipalities account for 3% of the fertilizer usage in Florida, pest control and environmental horticulture professionals accounted for 4%, and homeowners accounted for well over 50%! Defining which users are the most egregious will no doubt help in solving the long-term solution. Also, do you have benchmarks for residential usage? I, like many others, suggest that the current bans in the bay area will indeed change purchasing behaviors, but not usage. Certified pest control operators will comply because they (I) have a direct financial incentive to do so! Your quantitative data will be great, but informal qualitative studies of blog responses on media coverage (on TBO and other local news sites) seems to indicate that homeowners will not comply with the rulings. Again, isolating the worst offenders, if possible, will be beneficial. But to do so requires benchmark usage before the ban, usage during, who or what is the offending party.
3. According to the construct of your study, as described in the article on your website, samples will be taken from neighborhood storm water ponds and drains. Again, I cannot wait to see the results of your study. However, and I am no scientist (environmental, hydrological, or otherwise), thus I am no expert on your scientific methodology, and I accept there is a causal relationship between subdivision ponds and residential usage/non-compliance and subsequent runoff, but are you similarly taking samples of the bay? The whole purpose of the fertilizer bans is to help the bay. Longitudinal nitrogen data of the bay, and direct correlation with the new fertilizer ban periods on the bay, would also ultimately provide some valuable data. Would it not? Are there corollary studies and sample analysis directly on the bay being conducted in concert with this study?
I really appreciate your expertise on the aforementioned questions. Again, I am a landscape contractor, many people ask me questions about this issue. I know what the environmental lobby claims, and what my industry espouses. I follow my industry’s lead because I trust their science. If however there is fresh or contradictory data, I want to know about it, for my business, my community, and my industry. Once more, I am contacted by customers and citizens regarding our fertilizer usage. I try to relay, and answer folks questions, by framing both sides of the argument. But, on the aforementioned questions, I require clarification.
Will Womack, President
Tampa Bay Landscaping
We asked Nanette O’Hara, public outreach coordinator for the Tampa Bay Estuary Program to respond:
Thank you for your inquiry. Here are answers to your questions:
Our study will help to determine whether, and to what extent, the fertilizer bans are working. It is our assumption that communities which have a sales ban in place will show a greater reduction in nitrogen; our study is designed to test that hypothesis by measuring nitrogen levels in communities with different fertilizer ordinances (i.e. Hillsborough versus Pinellas).
1. Regarding nitrogen in reclaimed water, the amount varies according to the utility. But, overall, most reclaimed water in our area is not treated as thoroughly as wastewater that is directly discharged to the bay. The City of Tampa’s wastewater, for example, is treated to advanced standards which remove more than 96% of the nitrogen prior to discharge to the bay. The City of St. Petersburg’s wastewater, which is largely reclaimed for use on golf courses, medians, commercial properties and residential lawns, contains much more nitrogen. By our estimates, a homeowner irrigating twice a week with 0.75 inches of reclaimed water from St. Pete per irrigation would not need to apply any fertilizer at all to the lawn, per IFAS fertilization guidelines. The requirements for direct discharge of wastewater to the bay are much more stringent than those for wastewater that is reused for irrigation.
2. Our estimates indicate that nitrogen from urban fertilizer use comprises about 20% of the nitrogen carried in stormwater runoff to the bay. This is an extremely conservative estimate. Urban fertilizer refers primarily to residential fertilizer (single-family homes, condos, and office/retail complexes). Most of the local governments use very little fertilizer; Pinellas does not fertilize any of its properties anymore, except for athletic fields. Even the Florida Department of Transportation has stopped fertilizing highway medians and shoulders. As far as benchmarks for residential usage of fertilizer, studies conducted in the Wekiva Basin and other areas indicate that fertilizer use is highest in deed-restricted communities and especially in deed-restricted communities served by professional lawn care companies.
3. Our study will help to determine whether, and to what extent, the fertilizer bans are working. It is our assumption that communities which have a sales ban in place will show a greater reduction in nitrogen; our study is designed to test that hypothesis by measuring nitrogen levels in communities with different fertilizer ordinances (i.e. Hillsborough versus Pinellas). After one full year of a use and sales ban in Pinellas County, I can tell you that the overwhelming majority of homeowners are complying. In order for them not to comply they would have to drive to another county to buy fertilizer, and studies conducted by IFAS indicate that people buy fertilizer from the closest available store, NOT one in another county. They simply can’t buy fertilizer in Pinellas anymore that is not at least 50% slow-release nitrogen from October – May and 0% nitrogen from June – September. The retail stores are reporting no appreciable decline in sales of fertilizer, and they tell us that their customers are satisfied with the ordinance-compliant products they are offering. The list of compliant products continues to grow and Florida fertilizer companies have been very proactive about producing 50% slow-release N fertilizers and zero N fertilizers to meet demand. The majority of ordinance violations that were issued in Pinellas County (which enforces its ordinance very aggressively) were given to commercial fertilizer applicators. The most common violations were applying fertilizer right before or during a heavy rainfall, and leaving fertilizer granules on roadways and other impervious surfaces or blowing them into ponds or storm drains. However, I personally have worked with several lawn care companies that have been very supportive of the ordinance and pleased that BMP training is now required of all applicators in Florida.
4. Our study is indeed taking samples of nitrogen both in storm water ponds (in cross-sections of neighborhoods where the only source of nitrogen is lawn fertilizer) and in the receiving waters of the bay. We have tracked nitrogen loadings in Tampa Bay for close to two decades and have very good estimates on loads by bay segment as well as at smaller scales. For this study, we are especially interested in measuring nitrogen amounts at a very localized level (thus, storm water ponds) to ensure we are only measuring nitrogen from residential fertilizer and not from any other sources. Because storm water ponds within the bay watershed ultimately drain to the bay, then logically less nitrogen going into those ponds means less nitrogen going to the bay. But, yes, we are monitoring both the ponds themselves and the nearest bay waters they drain to. Our research may not give us all the answers to all the questions, but it will be the first real effort to scientifically quantify and compare the effectiveness of fertilizer ordinances. We know many people are awaiting the outcome of our research.
Originally published Winter 2012